Various types of tests related to patient diagnosis and therapy can be performed by analysis of a sample taken from a patient's infections, bodily fluids or abscesses. These assays typically involve automated analyzers onto which vials containing patient samples have been loaded. The analyzer extracts the samples from the vials and combines the samples with various reagents in special reaction cuvettes or tubes. Frequently, the samples are incubated or otherwise processed before being analyzed. Analytical measurements are often performed using a beam of interrogating radiation interacting with the sample-reagent combination, for example turbidimetric, fluorometric, absorption readings or the like. The measurements allow determination of end-point or rate values from which an amount of analyte may be determined using well-known calibration techniques.
Clinical sample analysis continuously needs to be more effective in terms of providing an increased number of advanced analytical options so as to enhance a laboratory's techniques for evaluating patient samples. Luminescent compounds, such as fluorescent compounds and chemiluminescent compounds, find wide application in the assay field because of their ability to emit light. Particles, such as latex beads and liposomes, have also been utilized in assays. For example, in homogeneous assays an enzyme may be entrapped in the aqueous phase of a liposome labeled with an antibody or antigen. Homogeneous immunoassays in which it is unnecessary to separate the bound and unbound label have previously been described for small molecules. These assays include enzyme channeling immunoassay, and fluorescence energy transfer immunoassay enzyme inhibitor immunoassays; fluorescence polarization immunoassay among others.
In view of this number of available analytical detection techniques, a modern clinical analyzer may include multiple detection units, each detection unit adapted to perform different measurements and follow various analysis protocols that the other detection units. The diversity of analytical detectors allows multiple types of tests to be run on the same system, thereby increasing the likelihood that an analyte can be determined by an assay that is most appropriate for that particular analyte, e.g., an assay that is highly specific for the analyte, is accomplished in a reasonable period of time, and is cost effective. In particular, an analyzer may include a detector adapted to detect luminescence of a reaction mixture in a reaction vessel as well as a photometer or turbidometer detector as well as a nephelometer detector as well as a yet another, different type of detector, such as an ion selective electrode, identified hereinafter as “ISE”. Clearly, accurately supplying the various different reagents required for such a range of different analytical detectors is an important aspect of maintaining analyzer throughput.